Boronizing is a process by means of which a wear and corrosion resistant coating is formed at a surface of a metal workpiece. The coating consists of a metal boride, such as an iron boride FeB or Fe.sub.2 B.
A typical boronizing process involves placing a metal workpiece to be boronized in a container. The container is then filled with a powdered mixture of materials from which the boron needed for the thermochemical reaction is derived. The container is placed within a large furnace and the contents of the furnace are heated to a selected temperature. Upon heating, the powdered materials react with the surface of the metal workpiece to form a boride coating as a protective layer. When a sufficient time has elapsed for the coating to be completely formed as a strong integral layer about the workpiece, the container is cooled and emptied. The boronized workpieces are removed for inspection, testing, cleaning and further heat treatment, if needed. Spent powdered materials are discarded or recycled to the extent possible.
Setting up a boronizing facility is a capital intensive endeavour due to the high capital cost of acquiring or constructing the furnaces that are required for the process. In addition, such boronizing facilities have high operational costs associated with the operation of the furnaces.